102 lines
2 KiB
Groff
102 lines
2 KiB
Groff
.TH ENV 1
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.SH NAME
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env \- set environment for command
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.SH SYNOPSIS
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.B env
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.RB [ \-ia ]
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.RI [ name\fB=\fIvalue "] ..."
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.RI [ utility
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.RI [ argument "...]]"
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.B printenv
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.RB [ \-ia ]
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.RI [ name\fB=\fIvalue "] ..."
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.RI [ utility
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.RI [ argument "...]]"
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.SH DESCRIPTION
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.B Env
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modifies its environment according to the
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.IB name = value
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arguments, and executes
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.I utility
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with the given arguments and the modified environment.
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.PP
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If no utility is specified then the modified environment is printed as
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.IB name = value
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strings, one per line.
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.PP
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.B printenv
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is identical to env in every way and is included for backward compatibility
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.SH OPTIONS
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.TP
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.B \-i
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Use exactly the environment specified by the arguments; the inherited
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environment is ignored.
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.TP
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.B \-a
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Specify all arguments for the utility, i.e. the first of the arguments is
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used as
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.BR "argv[0]" ,
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the program name. Normally the program name is
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.I utility
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itself.
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.SH ENVIRONMENT
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.TP 8n
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.B PATH
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The path used to find utility. It is as modified by
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.BR env ,
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i.e.
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.B not
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the inherited
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.BR PATH .
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.SH "SEE ALSO"
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.BR sh (1),
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.BR execvp (3),
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.BR environ (5).
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.SH DIAGNOSTICS
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The return code is
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.B 0
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after successfully printing the environment,
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.B 1
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on an error within
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.BR env ,
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.B 126
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if the
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.I utility
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could not be executed, or
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.B 127
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if
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.I utility
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could not be found. Appropriate diagnostic messages are printed on standard
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error.
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If
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.I utility
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can be executed then it replaces
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.BR env ,
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so the return code is then the return code of
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.IR utility .
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.SH NOTES
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When run from the standard shell
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.B env
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is only useful with options or without arguments. Otherwise the shell can
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do exactly what
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.B env
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can do, simply omit the word "env" on the command line.
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.PP
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One interesting use of
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.B env
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is with #! on the first line of a script to forge a PATH search for an
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interpreter. For example:
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.PP
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.RS
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#!/usr/bin/env perl
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.RE
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.PP
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This will find the Perl interpreter if it is within the user's PATH. Most
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UNIX-like systems have
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.B env
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in /usr/bin, but
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.B perl
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may be anywhere.
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.SH AUTHOR
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Kees J. Bot <kjb@cs.vu.nl>
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